In the lubrication art, zinc dithiophosphates have been utilized as multifunctional lubricant additives to provide antiwear protection as well as to inhibit oxidation of petroleum lubricants. Because of environmental and toxilogical considerations, it is desirable to provide lubricating oil compositions which are ashless and which do not contain phosphrous. Although ashless, non-phosphrous additives have been available in lubricant compositions to provide protection against either engine wear or oxidation of the lubricant, attempts to achieve both with a single additive have generally been unsatisfactory.
U.S. Pat. No. 4,382,869 discloses that reaction products of mercapthothiadiazoles and hydroxyl-containing or borated hydroxyl-containing unsaturated compounds such as oleyl alcohol have been found to be effective multifunctional friction reducing and corrosion inhibiting additives when evaluated in lubricating oils.